Optimal dosing levels for methadone treatment remain a controversial issue. In clinical practice, methadone programs tend to adopt "high dose" or "low dose" philosophies. Data from naturalistic evaluations of treatment clinic outcomes support the contention that low dose treatment is less effective than high dose, but there are few methodologically sound clinical trials comparing different dosing regimens under well controlled experimental conditions. The previous study conducted under this grant project has provided systematic data comparing the treatment outcomes status of patients assigned to low (0 or 20 mg) verses moderate (50 mg) methadone doses during a relatively short-term (180 day) treatment protocol. Preliminary data analysis suggests that the 50 mg treatment promoted better retention and reduced use of opiate drugs as compared with the lower methadone dosing regimens. Even at the 50 mg dose, however, considerable room for improvement was evident in retention as well as opiate and cocaine drug use. The present study proposes to follow up on previous findings by examining treatment outcomes at higher methadone doses. Specifically, the proposed study will compare outcomes for patients maintained on 40 - 50 mg versus 80 - 100 mg of methadone, dose ranges that correspond to the two extremes of currently accepted clinical practice. The present study will differ from the precious study in that a longer (40 week) period of maintenance will be examined and maintenance-eligible patients will be enrolled. Thus, the study will provide a systematic extension of our previous observations on the 50 mg dose from detoxification to maintenance eligible patients as well as providing new information about the incremental advantages of higher doses of methadone in drug abuse treatment. A range of outcome measures will be examined including treatment retention, opiate and cocaine drug use, and psychosocial adjustment as measured by the Addiction Severity Index. The study will provide valuable information in a contemporary population of drug abusers concerning the utility of treatment with methadone doses as high as 100 mg/day. These data will be clinically relevant and should make a useful contribution to policy consideration concerning optimal methadone treatment parameters.